[seqfan] A056619
israel at math.ubc.ca
israel at math.ubc.ca
Tue Feb 21 21:49:05 CET 2017
A056619 is "Smallest prime with primitive root of n or 0 if no such prime
exists." In the Crossrefs (what should probably be a Comment) says:
Here the primitive root may be larger than the prime, whereas in A023049 in
may not be.
and the Comment says:
a(n) = 0 only for perfect squares, A000290.
The Data has a(n) = 0 for squares < 99.
Well, I agree with that for even n, because if p is an odd prime a square
can't be a primitive root mod p. But I see no reason for that to be true
for odd n: all odd numbers, including odd squares, are primitive roots mod
2. So I think a(n) should be 2, not 0, for odd squares.
However, this being an old sequence, I hesitate to change the Data. What do
you suggest?
Cheers,
Robert
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